Two question about APPLYING INSTRUMENTAL FUNCTIONS

[Yuhao-9509]

Thank you very much for your work!In the part of INSTRUMENTAL FUNCTIONS, I have a few questions.
The first question is whether the Michelson Instrumental functions do not weight the center?
Code show as below：

def SLIT_MICHELSON(x,g):
    """
    Instrumental (slit) function.
    B(x) = 2/γ*sin(2pi*x/γ)/(2pi*x/γ) if x!=0 else 1,
    where 1/γ is the maximum optical path difference.
    """
    y = np.zeros(len(x))
    index_zero = x==0
    index_nonzero = ~index_zero
    dk_ = 2*np.pi/g
    x_ = dk_*x[index_nonzero]
    #Michelson:B(x)=\frac{2}{\gamma}\sin^2\left(\frac{\pi}{\gamma}x\right)/\left(\frac{\pi}{\gamma}x\right)^2
    #Original code：y[index_zero] = 1
    y[index_zero]= 2 / g
    y[index_nonzero] = 2/g*np.sin(x_)/x_
    return y

The second question is the wing width sampling point. If the center point of 0 is not sampled, will it cause wave number drift?
Code show as below：

def arange_(lower,upper,step):
    npnt = floor((upper-lower)/step)+1
    npnt = int(npnt) # cast to integer to avoid type errors
    upper_new = lower + step*(npnt-1)
    if abs((upper-upper_new)-step) < 1e-10:
        upper_new += step
        npnt += 1    
    return linspace(lower,upper_new,npnt)

Thanks again for your contributions!